Fluid flow sensors, also known as fluid flow meters or flow meters, are commonly used to measure the flow rate of a given fluid through a given area. This is useful in water and gas lines, in industrial applications such as factories, and so forth. There are many types of fluid flow sensors, which may be suited to different environmental conditions and different types of fluids. Mechanical sensors are common, but, because they contain moving parts, can be expensive to maintain. The cost issue has motivated the growing popularity of other types of sensors for fluid flow measurement, such as magnetic and ultrasonic sensors.
Ultrasonic sensors use ultrasound to measure the velocity of fluid with sound waves. In the most common variety, two ultrasonic transducers are spaced apart in or on a pipe. The transducers send and receive ultrasonic waves between one another. The rate of fluid flow can then be calculated as a function of the difference in travel time of the upstream and downstream waves. These sensors are sensitive to variations in temperature and pressure within the sensor body. Further, factors such as variations in pressure and temperature in the measuring region can alter the diameter or length of the sensor body, which can hinder the accuracy of measurement. This problem is especially prevalent for bodies made from plastic materials, due to the low rigidity and high thermal coefficient of expansion.
Thus, it should be appreciated that there remains a need for a sensor housing that minimizes variations in the size of the sensor body, in order to ensure an accurate measurement. The present invention addresses this need and others.